Two pole circuit breaker



Feb. 24, 1959 C. BRUNNER Two POLE: CIRCUIT BREAKER Filed Jan. 2, 1958 25 4 I4 Jil635 I n 6 55 & f 7 /4 1- 54 l 5 ff U `f i- D k l 29 2o u f E I 5o T T; fo 9 I i ///2 Fig'. I

Fig. 2

INVENTOR. CARL BEUNNEE pig United States Patent O TWO POLE `CIRCUIT BREAKER Carl Brunner, Floral Park, N. Y., assigner to Murray Manufacturing Corporation, Brooklyn, N. Y.

Application January 2, 1958, Serial No. 706,710

4 Claims. (Cl. 200-50) This invention relates to a two pole circuit breaker of the type comprising two single pole breakers mounted side-by-side for two pole operation, and more particularly to a unique arrangement for interlocking the tripping means of the two single pole breakers.

The idea lof combining two single pole breakers for two pole operation is not new; however, in the known arrangement the mechanism for interlocking the tripping means of the respective breakers is rather complicated in itself and requires modification in the design of certain functional parts in the two breakers.

As can be readily visualized, when combining two single pole breakers side-by-side, the adjoining walls are in contiguous relationship. In the known arrangement, these contiguous walls are each provided with a recess to accommodate the interlocking mechanism, and a projection, extending completely around the periphery. of the wall to define a fully enclosed chamber, when the two units are mounted side-by-side. rThe interlocking mechanism in the known unit is an arm-shaped member, pivotally operated near its center point. The size of the interlocking arm and the extent of pivotal movement are such that a recess of considerable dimensions is required. Since the casing and cover for the breaker are molded, the extensive modification to the molds for the walls of the breakers is expensive. In the highly competitive electrical industry, this additional cost is a significant manufacturing disadvantage.

Further, in the known unit, the interlocking mechanism is tripped by a breaker member specifically designed for this purpose. The design and manufacture of such a member adds again to the cost of the unit.

Still further, the interlocking mechanism of the known construction comprises several parts, necessitating first, fabrication of the several parts and, secondly, assembly of the parts into an integrated interlocking mechanism.

Accordingly, it is a first object of this invention to provide a two pole circuit breaker, comprising two single pole units and a unique interlocking member; the interlocking member being extremely simple in construction, consisting of a single part, and requiring no change in the operational components in either of the breaker units.

It is a further object of my invention to provide a two pole breaker which lends itself to a minimum of additional manufacturing cost, requiring essentially the same tools and manufacturing methods as that required for a single pole breaker.

It is a futher object of my invention to provide a two pole breaker, both poles of which are made to open practically simultaneously through the action of the interlocking member; with no significant time difference between the tripping of one pole and the consequent tripping of the other pole.

It is a feature of my invention to provide a two pole breaker requiring comparatively little change in the contiguous walls of the unit, for accommodating the interlocking member.

It is a further feature of my invention to provide an interlocking member which does not require close tolerances, either in itself or in the relative positions of the two single pole units, and which is amenable to mass production stamping techniques.

In accordance with an aspect of my invention, I pro vide a two pole electric circuit breaker comprising two trippable single pole breakers mounted side-byside. The single pole units are similar in construction and each comprise a member which is caused to move during the tripping of the breaker. My invention is characterized by an interlocking member consisting essentially of a single element connected to both of the movable members, in direct motion transfer relationship, whereby the movement of one of the movable members, caused by the tripping of the associated breaker is transferred to the other member producing tripping of the other breaker.

The above-mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

Fig. l is a side view of one of the single pole breakers with the cover removed;

Fig. 2 is a plan view of the interlocking member; and

Fig. 3 isv a partial perspective view of the two breakers, shown separated, and illustrating particularly the interlocking member in position in one of the breakers and the configuration of the wall accommodating the interlocking member.

In the 'following discussion, my invention will be described in conjunction with a specific type of circuit breaker; namely, an electromagnetic circuit breaker of the type described and claimed in a copending applica' tion, entitled Electromagnetic Circuit Breaker, Serial No. 667,847, filed June 25, 1957, and assigned to Murray Manufacturing Corporation. Although the ensuing description is specific to that type of breaker, it will be apparent at the conclusion of this description that my invention is useful in any type of breaker or switch which has at least one moving part, which movement is correlated to the tripping of the breaker.

In lorder to understand the invention, it is necessary to know generally the principles of operation of the circuit breaker.

Therefore, referring first to Fig. l, a single pole circuit breaker is illustrated, comprising a casing 1 made of insulating material, such as Bakelite, for accommodating the several parts constituting the breaker.

The electrical circuit comprises an input in the form of a spring clip 2, for engaging a blade of a bus bar (not shown), and an output at the opposite end of the breaker in the form of a wire connector 3.

The electric circuit between the input spring clip 2 and the output wire connector 3 is completed by a coil 4 connected at one end 5 to the clip 2 and at the opposite end 6 to a flat resilient contact member 7 carrying a contact 8 at an end thereof, for engaging a complementary contact 9 attached to an extension 10 of the wire connector 3. Thus, when the contacts 8 and 9 are closed, a circuit is completed from the input 2 to the output 3.

The coil 4 constitutes the winding of a solenoid 11. The solenoid 11 comprises a hydraulically sealed, non magnetic tube 12 known as a magnetic time delay tube. The coil 4 is maintained in position between an end pole piece 13 and a shoulder member 14 made of magnetic material.

One of the primary functions of the circuit breaker is to protect a circuit by opening automatically in response to a short circuit or a continued overload. This automatic protection is provided by a control mechanism comprising a top armature 15 coupled to a side armature aardse@ 16 and "a 'slide assembly 17,' on which the side armature 16 bears.'- The armatures are made .of magnetic material and serve partially to complete a magnetic circuit for the solenoid. Y

The ltop armature is inthe shape of a-at bar provided vrwithza hole through which the upper part of tube i 12 extends.Y One'end of the top armature rests on a support 18 extending from the casing 1.

The side armature 16 is also in the shape of arat bar Y and is coupled to the top armature 15 by anend portion- 19 fitting into a slot in the top armature.

The'lower end of the side armature 16 is off-set with a right-.angular portion, as shown. Y The right angular portion bears on the slide assembly 17. The lower portion t20 ofthe side armature is narrowedto fit freely 4in an opening 21 ofA a trip armature 22. The trip armature completes the magnetic circuit and its function will be described later in conjunction with the automatic:l 1. opening ofV the contacts.

the open position by a spring 28 which is stretched double pole operation, means is provided for interlocking the tripping members of the two units.

As is apparent from the above discussion, the movement of the side armature 16 is directly related with the tripping of the breaker. I utilize this motional force of the side armature to trip the adjoining single pole breaker.

The side armatures are interlocked for tripping by a cross shaped member 3d, best seen in Fig. 2. The interlocking member is made preferably from fiat sheet insulating material byV a blanking operation. The cross l arms 35 are each provided with a slot 36 extending from the respective ends towards the centerthereof..

The interlocking member is slidably mounted and symmetrically positioned in respective recessesl 37 provided therefor in the contiguous walls of the two breakers. The

recesses are suiciently long to permit a predetermined length of slidable travel.

The cross arms enter into the respective breakers through slots 38, cut-out or formed in the recessed portions 37. The cross arms 35 are located in the breakers so that the side armatures are positioned within the slots 36 (Fig. l).

when the handleis pivotedto the operated position. Thev bottom ofthe handle is cam shaped with the corner of the angle acting directly on the top armature which serves as the cam' follower. When the handle is moved forwardly, the angle corner thereof causes the top armature' tovbe pivoted downwardly about the supporti-18,

therebydepressing the side armature 16. The side armature is moved down on the slide assembly 17, and is positioned to exert substantially only a radial force on the roller -23 so that the roller has no tendency to turn.

When the handle Z6 is moved fully forward, so that it is pivoted slightly beyond the equilibrium point of the angle corner, the slide assembly-17 is depressed toits fullestextent, thereby correspondingly moving the spring contact 7 and closing the contacts 8 and 9.

Automatic overloadv tripping is initiated by the trip The corners of the cross arms are chamfered as shown to permit easy guidance, first, of the arms through the wall slots, and second, of the side armatures into the slots 36.

In order to understand the operation of the interlock- Y s ing member, let us assume that the breakers are first closedf i. 'e., the respective side armatures 16 are on the rollers 23' and pressure is exertedlup'wardly by the Vspring contact members 7.l When one single'pole breaker` of the two pole breaker' trips, .the side armature of that f breaker will be moved beyond the point of stability on the roller. `.The spring contact member 7 thereupon D forces the slide assembly 17 upwardly (as illustrated ini the figure) which moves the side armature completely.

off the roller. The required force to move the side arma@ J ture from its rest position to the point just beyond stability is critical and must be predetermined, so that'the breaker can becalibrated accordingly. Therefore, it is important that this initial movement of the side armature be unimpairedby the interlocking member. Accordingly, the width of the slots 36 in the cross arms.35 is armature 21. The'trip armature is in the shape of an angle plate having one leg 29 positioned alongside the side armature and the other leg 30 below the polepiece 13 of the solenoid. As shown in Fig. 1, the leg 29 is provided with lugs 31 rockably mounted in depressions in the casing. Thek vseparation of leg 30 from the pole reach the point of instability for tripping independently.

piece 13 is limited by a projection 32 extendingv from the casing 1.v

Theileg 30'is normally urged against the'projection 32 by a. second coil spring; only one end thereof S33 being.. showin in the-figure. The Yend of the spring bears against the leg 29.

UponQthe occurrence of a short circuit, or continuedV overload, the solenoid will develop sufficient force'to` attract'the trip armature, which strikes. the side armature..L The trip armature imparts la forceto the side armature Vwhichtisftangential to the surface of the roller,

thereby causing the roller to rotate and V-trip the side.

' selected to permitV free initial movement.

stability, it contacts and moves sufficiently the cross member to cause the second breaker to trip. Thus, the effective tripping motion is transferred to the second breaker. prior to the opening of the contacts in the first breaker@ Thisproduces practically simultaneous tripping action.

Thus, it is apparent that eachsingle Ipole breakerV can of the other, and that the force needed to trip the second breaker is derived from a member (spring contact 7) whosemovement is independent of the forces directly involvedin tripping the breaker. l

The vcross member isfully slidable andreturns 'to its on and otf'position with the side armatures; each of the'V side armatures being urged to the position shown by the coil spring 24.

armature. The slide assembly is-thereupon immediately 1 forced upwardly-bythe spring contact 7 whichY opens`I the contacts 8 and 9.

j Fora -more detailed descriptionofthe circuitbreaker,

reference' is made to the aforementioned copendingpat-i.

ent application. i.

In accordancefwiththis 'inventionl'two Ysuch' singleilpolet' breakers are mounted: side-byside :for Ydoubleupolef-operationzlfl Since Atwo vindependentunits' are coupled fo'r 75' If the side'armature of one breaker should be slipping' f off the roller when closingj the cross member will not permit the sidearmature of the second breaker to engage l its roller, thereby preventing the closing of one breaker while the other remains open In order to protect the interlocking mechanism from dust, the adjoining walls are each provided with a rim 1 40 which extends approximately two-thirds around the perimeter of' the wall. A short .section of the chamber is left open to permit ventilation of the chamber.

To facilitate the assembling'of' the two singl'epclejbreakers`,'the adjoining walls1 are provided respectively" Withalignedfproje'ctions. *Therprcjectionsare bored'to receive any suitable fasteners, such as bolts and nuts. A

Immediately t upon the side armature moving beyond this point of if.

handle spacer 41 is provided between the two handles and is rigidly fastened thereto by any suitable fastener means.

While I have described above the principles of my invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of my invention as set forth n the objects thereof and in the accompanying claims.

What is claimed is:

l. A two pole electric circuit breaker comprising two trippable single pole breakers mounted side-by-side, the single pole breakers being similar in construction and each comprising a trippable member which is caused to move in a given direction during the tripping of the breaker, a slidable interlocking member consisting essentially of a single element connected to both of the trippable members in direct linear motion transfer rela tionship, the direction of travel of said interlocking member being aligned with said given direction, whereby the movement of one of the trippable members, caused by tripping of its associated breaker is transferred to the other member producing tripping of the other breaker.

2. The breaker according to claim l, wherein said interlocking member is in the shape of a cross, the cross being positioned so that the arms thereof extend respectively through openings in the adjacent breaker walls to engage said movable members.

3. A two pole circuit breaker comprising a pair of single pole electromagnetic circuit breakers; each single pole breaker comprising a pair of contacts, one contact being connected to a flat resilient member, the resilient member being tensioned so that said contacts are normally separated, a slidable assembly positioned to bear against said resilient member and movable in a direction to close said contacts, said slide assembly comprising a roller rotatable on a shaft mounted perpendicular to the direction of movement of said slide assembly, an armature in the shape of a bar having an oE-set portion at one end thereof, movable in respectively radial and tangental directions relative to said roller, means positioning said armature so that said off-set portion normally bears radially on the surface of said roller and in the direction of travel of said slidable assembly, means for depressing said armature against the force of said resilient member when it is desired to close said contacts, and tripping means adapted to apply a tangential force to said armature sucient to move the off-set portion beyond the point of stability on said roller, whereby the tension of said resilient member forces said armature completely off said roller; means rigidly mounting said single pole breakers side-by-sde, a slidable interlocking member in the shape of a cross mounted in recess portions in the adjoining walls of the pair of breakers, the direction of travel of said interlocking member being aligned with the tangential movement of said armature, the arms of the cross having slots at the ends thereof extending through respective openings in the breaker walls and positioned to engage said armatures, the armatures tting into said slots, whereby the tangential motion of said armature in the tripping breaker is directly transferred to the armature in the adjoining breaker causing tripping thereof.

4. The breaker according to claim 3, wherein said armatures are respectively positioned on said rollers so that a predetermined amount of tangential movement is tolerated before the point of instability is reached, and the width of the respective slots at the ends of said cross arms being selected to permit freely this tangential movement.

Krantz June 10, 1919 'Thomas Ian. 29, 1957 

